Question: Khan.scratchpad.disable(); To move up to the maestro level in his piano school, Ben needs to master at least $164$ songs. Ben has already mastered $25$ songs. If Ben can master $5$ songs per month, what is the minimum number of months it will take him to move to the maestro level?
Answer: To solve this, let's set up an expression to show how many songs Ben will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Ben Needs to have at least $164$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 164$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 164$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 5 + 25 \geq 164$ $ x \cdot 5 \geq 164 - 25 $ $ x \cdot 5 \geq 139 $ $x \geq \dfrac{139}{5} \approx 27.80$ Since we only care about whole months that Ben has spent working, we round $27.80$ up to $28$ Ben must work for at least 28 months.